Multiplication of numbers in base 2 - JSS1 Mathematics Lesson Note

Multiplying binary numbers is similar to decimal multiplication but simpler because there are only two possible digits (0 and 1). Multiplication in binary can be broken down into multiplying each digit of one binary number by each digit of the other binary number and then summing the results. For example:

   101   (5 in decimal)

x   011   (3 in decimal)

--------

   101   (5 in decimal)

  000    (0, shifted one place to the left)

+ 101     (5, shifted two places to the left)

--------

  11011   (15 in decimal)